> What's the benefit of this? Seems like a very niche feature.
Cross organizational communication, e.g. across ministries (like France realized it with 60 Matrix servers), across different offices of companies, across multiple companies, across universities (which was e.g. important for TU Dresden).
In principle it is the same with Email.
> What other use could there be?
> I'd want a software that does one thing well because to this day there isn't even a chat solution that rules all the others.
Matrix is a protocol, not a software. Specifically it is a communication protocol. So anyone can create software that needs communication which benefits from properties that Matrix provides, can use it independently of the software you are using to chat.
If you can only talk to other people on your own server, then the application is limited to just team chat.
Matrix clients have the potential to be much more. You can use the same account for various team chats and still use it like a messaging app for your friends and arbitrary personal groups.
Maybe most importantly, federation provides resilience against bad server operators. If Signal had allowed federation, it wouldn't have been a big deal to ditch its servers when they introduced a sketchy cryptocurrency onto the platform. Because they don't allow it, everyone was locked in.
What's the benefit of this? Seems like a very niche feature.
> Most of the time this is used to create an instant messaging service, but it can be used for much more.
What other use could there be?
I'd want a software that does one thing well because to this day there isn't even a chat solution that rules all the others.